JPS63309615A - Heat-resistant organic synthetic yarn having excellent high-excellent configuration stability - Google Patents

Abstract

PURPOSE:To obtain polymetaphenylene isophthalate yarn having a specific melting point, specific crystallinity, specific elongation and specific dry shrinkage factor, excellent fiber performance and improved configuration stability even at high temperature. CONSTITUTION:Aromatic polyamide yarn which has a repeating unit shown by formula I [Ar1 is bifunctional phenylene residue shown by formula II or formula III (R is H or CH3) and has repeating unit with at least one CH3 at the ortho position of phenylene group C directly bonded to N of amide bond; Ar2 is bifunctional phenylene residue shown by formula IV and has repeating unit containing carbonyl carbon atom of amide bond directly bonded to 1, 3 positions or 1, 4 positions of phenylene group C and the ratio of 1, 3 position form:1, 4 position form of 100:0-80:20, melting point Tm, heat generation starting temperature Tex, crystallinity Xc, elongation DE, dry shrinkage factor DSR (Tm) at the melting point and dry shrinkage factor DSR (Tm+55 deg.C) at the melting point+55 deg.C which satisfy equations V-X.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention relates to a heat-resistant organic synthetic fiber that has excellent high-temperature dimensional stability unlike existing organic synthetic fibers. Conventional technology) Organic synthetic fibers have excellent fiber performance and are widely used in everything from clothing to industrial materials. was the main focus, and its use was extremely rare.

However, in recent years, advances in organic synthetic chemistry have been combined with diverse needs ranging from general clothing and industrial materials to aerospace development, and the development of organic synthetic heat-resistant fibers has been actively promoted. As a result, various organic synthetic fibers have been created. Among these, the one that has been most successful on a commercial scale and is considered to be the most representative is meta-based wholly aromatic polyamide fiber, whose chemical composition is mainly composed of polymethaphenylephthalamide (hereinafter abbreviated as PMIA). It is said that

This PMIA fiber has a temperature higher than that of existing synthetic fibers.
It can be used in a temperature range as high as 0 to 200°C, and has general performance required as a general-purpose product, such as a balance between strength and elongation, flexibility, and post-processability. In addition, it is highly flame retardant, exhibiting ``self-extinguishing'' properties that emit little flame even when the fibers burn, and immediately extinguishes when the flame is moved away. It has been widely used in the field of clothing, such as heat-resistant protective clothing such as firefighting suits, aviation suits, and fire vests, and even in the bedding and interior design field, and continues to expand to this day.

However, it has been found that this PMIA fiber is not sufficient to meet the requirements for morphological stability at high temperatures, for example, above the melting point, in clothing applications, such as materials for heat-resistant and protective clothing. As a countermeasure to this problem, it has been proposed to use a small amount of para-based wholly aromatic polyamide fiber (Tata et al.
Plastic 36.34.1985). According to this method, the shape stability at high temperatures is improved depending on the blending ratio, but since the elongation of the rose-based wholly aromatic polyamide fiber is extremely low and the rigidity is extremely high, it cannot be as flexible as for general clothing. The disadvantage is that the quality decreases.

PMIA fibers do not melt during combustion and do not cause melt drips, but the fibers undergo a large change in shape due to heat shrinkage, and the fibers also become tightly fused together. In the event of a disaster, it may become difficult to take off clothes, causing problems such as burns and other injuries.

(Problems to be Solved by the Invention) In view of the above-mentioned problems of PNIA delicacy, the present inventors have discovered that it has the same general fiber performance as existing general organic synthetic fibers, and at the same time has excellent form stability at high temperatures. In other words, in order to obtain a heat-resistant organic synthetic R fiber that has a small thermal shrinkage rate even at high temperatures above the melting point and that does not firmly fuse the fibers together during combustion, we have improved the polymer synthesis side, the fiber manufacturing side, and the fiber. The present invention was arrived at as a result of various studies from the viewpoint of physical properties.

(Means for Solving the Problems) That is, the present invention provides fibers made of an aromatic polyamide having characteristics satisfying the following formulas (1) to 6), wherein the aromatic polyamide has the formula [I] Aromatic polyamide fit Pa having a repeating unit represented by:

Tm4350℃・・・・・・・・・(
1) Tm-Tex≧30°C (2)
Xc≧10chi ・・・・・・・・・(
3) DE≧lOchi ・・・・・・・・・
・(4) DSR(Trn)≦15% −・
...-(5) (where Tm: melting point, Tex: exothermic start temperature, XC: crystallinity, DE = fiber elongation, DSR (Tm): dry heat shrinkage rate at melting point, DSR (T
m+55℃): Dry heat shrinkage rate at melting point +55℃)) IN-Art-NHOC-Arz-Co-)
It is a divalent phenylene residue represented by -...--[I]. Here, R1 represents hydrogen or a methyl group, and has a repeating unit having at least one CHs group at the ortho position of the phenylene carbon atom directly connected to the nitrogen atom of the amide bond. Arz is a divalent phenylene residue represented by ゝ@辷, the carbonyl carbon atom of the amide bond is directly connected to the 1.3-position or 1.4-position of the phenylene group carbon atom, and the 1.3-position: 1.4 position is 100:0-80
: Having repeating units in the range of 20. )
”.

Note that the characteristic values and physical property values referred to in the present invention represent numerical values observed using the measuring instruments and measurement conditions described below, respectively.

Tm: Approximately 1O' by Elmer's DSC-2C in melting point bar
A 1Ig sample was placed in an A1g sample dish in a nitrogen gas stream (3
A DSC curve from room temperature to a predetermined temperature is obtained at 10° C./min at 0x//min), and its endothermic peak temperature is defined as Tm.

Tex: Exothermic start temperature A sample of approximately 1 ornf was placed in an Al sample pan using a Perchielmer DSC-2C and heated in a nitrogen gas stream (30 WL/
/m1n) per minute at 10°C from room temperature to the specified temperature.
A C curve is obtained, and its exothermic start temperature is defined as Tex.

XC: Crystallinity Rotating anticathode ultra-strong X-ray generator RAD-R manufactured by Rigaku Denki Co., Ltd.
A (40 KvlOOmA, CuK2 ray), and while rotating the sample in a plane perpendicular to the X-ray beam, the diffraction angle 2θ was adjusted.
An X-ray diffraction intensity curve in the range of =5 to 35 is obtained, and then the diffraction curve is separated into a crystalline region (A) and an amorphous region (Aa), and the value Xc calculated by the following formula is defined as the degree of crystallinity.

Xc=(Ac/(Ac+Aa))xloo(S)BE:
Fiber elongation was determined by conducting a tensile test using an Instron tensile testing machine under the following conditions: sample length 10, tensile speed 5 t*/5 minutes, initial load 0.05 f/d.

In the present invention, the fiber must satisfy the following formulas (1) to (4).

Tm≧350'C-°°°-River-1) Tm-Tex
≧30℃・・・・・・・・・(2)Xc≧
lOchi ・・・・・・・・・(3)D
E≧lOchi ・・・・・・・・・(4
) That is, in the aromatic polyamide fiber of the present invention, Tm
(melting point) is 350°C or higher, and Tex
It has been found that when the (exotherm onset temperature) is 30°C or lower (Xc (crystallinity) is 10- or higher, the fiber has excellent morphological stability even at high temperatures higher than the melting point).

In other words, even when Tm is 4350°C and Xc≧10-, Tm-Tex is 30°C or more and Tm
- When comparing fibers with a Tex of less than 30°C, the former, that is, the Tex (thermal decomposition initiation temperature) is higher than the Tm (melting point) at 30°C.
The lower the value, the better the morphological stability at high temperatures above the Tm (melting point) of the fiber, compared to the latter, that is, the Tex is less than 930° C. than Tm. This may seem reasonable, but surprisingly, it actually turns out to be T.
The lower the ox, the better the morphological stability.

The exact reason for this is not well understood, but Tm≧3
50℃, Xc≧10t or T e X Z>E
In the fiber of the present invention, which is 30°C or more lower than Tm, thermal decomposition begins at a relatively low Tex, so it occurs slowly and mainly in the amorphous region.At that time, microcrystals exist in the crystalline region without melting. Therefore, the microcrystals act as restraining points for the molecular chains against thermal contraction that occurs as the orientation of the oriented molecular chains in the amorphous region is relaxed due to heat. It is thought that a type of crosslinking occurs between molecular chains and a three-dimensional structure is formed, resulting in good morphological stability even above the melting point.

On the other hand, even if Tm≧350℃ and Xc≧10%, if Tex is lower than Tm by less than 30℃, thermal melting occurs before a three-dimensional structure is formed due to sufficient intermolecular crosslinking. Therefore, it is thought that heat shrinkage and fusion between fibers were large, resulting in poor polymorphic stability.

Because of this, the range of Tm-Tex is Tm-Tex≧30℃
preferably Tm −Tex ≧50°C
More preferably, Tm-Tex≧70°C.

Although the fibers of the present invention have good morphological stability even at high temperatures above Tm (melting point), other fiber properties deteriorate to some extent at temperatures above Tm, so compared to general synthetic fibers.
In order to be a heat-resistant fiber that can be used practically even at temperatures as high as 00°C or higher, Tm must be 350°C, preferably Tm 400°C, and more preferably Tm 420°C.

In addition, even if Tm≧350℃ and Tm-Tex≧30℃ are torn, if the crystallinity is small (!
From around the glass transition point, which is a much lower temperature, thermal shrinkage increases rapidly and form stability becomes poor.

For these reasons, it is necessary that Xc≧10chi,
Preferably, Xc≧15.

Furthermore, in order for the fiber to be used in the same way as existing organic synthetic fibers in applications such as clothing and industrial materials, good flexibility and processability are essential conditions. For this purpose, it is important to have a sufficient balance between strength and elongation, as well as sufficient wrinkle elongation, and DE (fiber elongation) must be ≧lO%. Preferably DE) 15%, more preferably D
E) It is 20 chi.

Next, in order to further improve the shape stability of the fiber of the present invention at high temperatures, the fiber must satisfy the following formulas (5) and (6).

DSR (Tm) 515% ・・・・・・・・・
(5) Here, DSR (Tm) is the dry heat shrinkage rate at the melting point, and DSR (Tm + 55°C) is the dry heat shrinkage rate at the melting point + 55°C.

DSH was measured as follows.

That is, a load of 0.1r/a is applied to the fiber sample and its length t
After measuring o, it was free-processed for 10 minutes in a hot air dryer at a predetermined temperature, and then after 30 minutes, a load of 0.1 r/d was applied again to measure the sample length t1, and the drying shrinkage rate DSR was determined by the following formula. I asked for

to -tI D S R = -X 1 0 0 Chi t.

If the DSR (Tm) exceeds 15%, dry heat shrinkage is already large at the melting point, and the shape stability cannot be said to be good. Even with a DSR (Tm) of 515%, heat shrinkage increases rapidly, so if you are wearing heat-resistant protective clothing and are affected by an earthquake, it may be difficult to remove it, resulting in even greater damage such as burns. It is important that the thermal shrinkage be sufficiently small even at temperatures higher than the melting point of +55°C.

The fibers satisfying the above (1) to (6) in the present invention can be produced by using an aromatic polyamide polymer having a repeating unit specified by the following formula [■].

MoNH-Arx-NHOC-Arz-CO-)--
-...- [I) is a divalent phenylene residue. R represents hydrogen or a methyl group, has at least one CHs group at the t-position of the phenylene carbon atom directly connected to the nitrogen atom of the amide bond, and has a repeating unit.

Arz is a divalent phenylene residue represented by @, and the carbonyl carbon atom of the amide bond is directly connected to the 1.3- or 1.4-position of the phenyl group carbon atom, and the 1.3
Position: 1.4 position has a repeating unit in the range of 100:O to 80:20. ) where Arx has at least one methyl group, Tex is Tm-30
When the temperature is below ℃, the methyl group is oxidized at temperatures above T@X and causes reactions such as crosslinking to form a three-dimensional structure, which is thought to contribute to improving the morphological stability at high temperatures above the melting point. . Furthermore, as will be described later, the fibers of the present invention have dyeability at a dyeing level, which is due to the increased affinity for solvents due to the substitution effect of the methyl group in Ar1K.
This seems to be due to favorable effects such as an increase in dyeing rate.

Therefore, it is preferable that Arr is substituted with at least one methyl group, and even more preferable effects are exhibited when the substituent R is a dimethyl substituent, in which the substituent R is a methyl group. Further, the nitrogen atom of the amide bond directly connected to the phenylene group of Ar1 is directly connected to the carbon atom at the 1.4-position of the phenylene group,
The carbonyl carbon atom of the amide bond directly connected to the phenylene group of Ar2 is at the 1.3 or 1.4 position of the phenylene group carbon atom, and the 1.3 position: 1,4 position is 100
:0~80:20 is preferable. The reason for this is that in cases outside these ranges, even if all other items are satisfied, the regularity of the molecular structure forming the polymer will be significantly disturbed, resulting in a decrease in crystallinity and Xc≧10%. This is because the desired fibers cannot be obtained.

As can be seen from the above reasons, in the present invention, aromatic polyamides having a particularly preferred structure have 95 repeating units.
moles or more of 2-methyl-1,4-phenyleneiso7talamide and/or 5-methyl-1,4-7dinileneisophthalamide, or 3,6-di)f-1,4-
Phenylene inphthalamide / and /l or 2,5-
Dimethyl-1,4-phenylene isophthalamide and also mixtures of these repeating units are preferred.

Furthermore, an aromatic polyamide in which 95 moles or more of the repeating units are 2,5'-dimethyl-1,4-biphenylene/-inphthalamide and/or 3,6-dimethyl-1,4'-biphenylene-isophthalamide. Fibers are preferred.

An aromatic polyamide having a specific structure that satisfies the present invention can be easily produced by a known production method. That is, aromatic diamine and aromatic dicarboxylic acid halide can be produced by low-temperature solution polymerization, low-temperature interfacial polymerization, melt polymerization, or the like. It can also be produced by high temperature solution polymerization from aromatic diincyanate and aromatic dicarboxylic acid.

In the present invention, a polymer having a specific repeating unit can be specified as the aromatic polyamide having excellent high-temperature morphological stability, but in particular, it is possible to specify a polymer having a specific repeating unit. can be manufactured. For example, according to the method of Japanese Patent Application No. 60-030529, using diincyanate and carboxylic acid as raw materials, N, N'
- An aromatic polyamide can be produced by heating polycondensation using dimethylethylene urea as a solvent and an alkali metal compound as a catalyst at a temperature of 100°C to 200°C. According to this method, a high-molecular-weight polyamide solution with good color and capable of forming fibers is produced in one step, and a polymerization solution is produced in another step. Alternatively, it is preferable because it can be concentrated and used as a spinning stock solution in some cases.

Examples of aromatic diamines used as raw materials for producing the aromatic polyamide of the present invention include 2-methyl-P-phenylene diamine, 2,5-dimethyl-P-phenylene diamine, and 3,3'-dimethyl- 4,4'-biphenyldiamine, aromatic diiso'/ane),! =L-
t”H2-methyl-P-phenylenediinocyane),
2.5-dimethyl-P-phenyl diisocyanate,
3,3-dimethyl-4,4'-biphenyl diisocyanate. Examples of the aromatic dicarboxylic acid include isophthalic acid and terephthalic acid, and examples of the aromatic dicarboxylic acid civalide include isophthalic acid and terephthalic acid dichloride.

dichloride etc. As a base component, the nitrogen atom in both diamine and diisocyanate is 1,4 of the phenylene group.
Although it is a coordinator, the acid component is dicarboxylic! ! The carbonyl carbon atom of both dicarboxylic acid halides is preferably a 1,3-coordination form of a phenylene group, and may contain 20 mol or less of a 1,3-coordination form depending on the case.
If the amount is more than this, it is impossible to obtain a film or fiber made of the desired crystalline polymer and having good high-temperature dimensional stability.

The aromatic polyamide fiber with excellent high-temperature morphological stability according to the present invention may be produced by any known method, but
In the case of aromatic polyamide, it is preferable to produce it by dry spinning or wet spinning.

In particular, in the case of the polyamide with a specific structure according to the present invention, as mentioned above, the present inventors separately invented the patent application No. 60-0305.
The polymerization solution prepared by the method of No. 29 is used as a spinning stock solution, for example, stock solution temperature: 30°C to 100°C, coagulation bath composition: Caα 230 to 50% aqueous solution, coagulation bath temperature: 50°C.
Wet spinning at ~100°C in a hot water bath, followed by 1.1 to 5 times wet heat stretching in an aqueous solution bath with almost the same composition as the coagulation bath, and then washing in hot water at 50 to 100°C. After doing enough.

Hot air drying at 100-200℃, followed by drying at 300℃-4
The homogeneous heat-resistant aromatic polyamide fiber of the present invention with excellent shape stability at high temperatures can be produced by carrying out a dry heat stretching heat treatment of 1.1 to 5 times in air or an inert gas bath at 50°C. Can be done.

(Effects and Applications of the Invention) The fiber of the present invention has well-balanced general fiber performance represented by strength, elongation, and Young's modulus that are almost the same as existing organic synthetic Fa fibers, such as polyethylene terephthalate fiber, and existing heat resistance. Aromatic polyamide fiber has properties that PMIA fiber does not have, that is, it has small heat shrinkage even at high temperatures above the melting point, and the fibers are strong together during combustion.
It has excellent morphological stability that does not cause D. Further PM
Regarding poor dyeability, which is said to be one of the biggest drawbacks of IA fibers, the fibers of the present invention are much better than PMIA fibers and are at a practical level. Therefore, it can be used in a wide range of applications, from protective clothing to bedding to interior decoration, which takes advantage of heat resistance and high-temperature shape stability, as well as dyeing. It is not limited by the example described.

Example 1 Isophthalic acid 166, Or (0,9991 mol), isophthalic acid monopotassium salt 2.040 f, anhydrous N in a 3J capacity separable flask equipped with a stirrer, thermometer, condenser, dropping funnel, and nitrogen inlet tube. .

N'-dimethylethylene urea 2000Rt ff12
It is charged under atmosphere and heated to 200° C. with stirring on an oil bath. Trilene-2 while maintaining the contents at 200℃
,5-diisocyanate) 174.1F (0,9994
Mok) Wom water N, N'-dimethylethylene urea 2
A solution dissolved in 00d was added dropwise through the dropping funnel over a period of 2 hours, and the reaction was continued for an additional hour, after which heating was stopped and the mixture was cooled to room temperature. A portion of the reaction solution was poured into strongly stirred water to precipitate a white polymer, which was further washed with a large amount of water and dried under reduced pressure at 150°C for about 3 hours. 1 image, 30℃)
was 1.9. Also, the polymer concentration of the polymerization solution is about 11
．． At 4% by weight, the viscosity of this solution was 380 voids (Type B viscosity 1ti50°C). Moreover, the obtained polymer is I
It was confirmed by R spectrum and NMR spectrum that it was poly(2-methyl-1,4-phenylene isophthalamide).

Prepare the spinning stock solution. Then, while maintaining the temperature at 50°C, 8 ink was applied from a nozzle with a hole diameter of 0.11cm and a number of holes of 600 (each hole was circular).
Discharge at 54.5 f/min into an aqueous coagulation bath containing 40% Ca02 maintained at 0°C. The filament discharged from the nozzle passes through a coagulation bath, then undergoes thermal stretching in a bath with the same composition as the coagulation bath at a rate of about 1.6 times, and is thoroughly washed with water in a washing bath consisting of 80°C hot water. An oil agent is applied and drying is carried out through a hot air bath at 150° C. to obtain a wet-heat drawn spun yarn.

The spinning yarn has an oval cross section but is homogeneous and has a diameter of 2900
-7'neel/600 filament. Next, this spun yarn was subjected to dry heat stretching at a stretching ratio of 2.4 times using a nitrogen flow hollow dry heat stretching machine maintained at 430°C. phenylene isophthalamide) #R fiber was produced.

The physical properties of the obtained fibers are single yarn denier -2, 1, 1 degrees =
5.3 f/dr, elongation = 26.5%, Young's modulus =
90 r/d, Tm=421℃, Tox=327℃, T
m-Tex=94°C, Xc=24%, DSR(Tm)=
DSIL (421℃); 12%, D reed, good general f
It shows Jl fiber physical properties and excellent morphological stability at high temperatures above the melting point.

Next, when we created a cylindrical knitted fabric using this fiber and conducted a combustion test using it, it clearly showed self-extinguishing properties that extinguished fire immediately when the fire was kept away. The fibers were not firmly fused together.

A dyeing test was also conducted on this fiber. The dyeing conditions were 59 g Io, w, f of disperse dye, dyeing temperature 140° C., dyeing time 60 minutes, and using a carrier.The red dyeing rate was 72 cm, and the color was dyed to a medium color or higher.

Example 2 Polymerization was carried out using the same equipment and method as in Example 1. Inphthalic acid 166.1f (1,000 mol), isophthalic acid monopotassium salt 2.005F, anhydrous N,N'-dimethylethylene urea 210 Q+m were charged, heated and dissolved at 200°C, and after 2.5 - A solution containing 188.2F (1,000 mol) of dimethyl-1,4-phenyl diisocyanate dissolved in 200 mK of anhydrous N,N'-dimethylethylene urea was added dropwise over 2 hours. During this time, the entire solution gradually became cloudy, and by the end of the dropwise addition, it had become a milky, heterogeneous system. After further reaction for 1 hour, it was cooled to room temperature, and the -S of the polymerization solution was treated in the same manner as in Example 1. The logarithmic viscosity of the obtained polymer was 1.6. Anhydrous calcium chloride powder was added in an amount of 1% by weight to this polymerization solution, and a homogeneous solution was obtained with stirring at room temperature. The viscosity of this collapsing liquid was 580 voids. The above polymerization liquid was made into fibers in the same manner as in Example 1. The physical properties of the obtained fiber were: single yarn denier = 2.1, strength = 5
．． 7 f/dr, elongation = 25.2%, Young's modulus = 11
6 r/d%Tm=427℃, Tex=332℃,
Tm-Tex=95℃, Xc=25%, DSR(Tm
) = DSR (427°C) = 11%, DSR (482°C)
A cylindrical knitted fabric was prepared using the fibers of the present invention, and a combustion test was conducted using this fabric.The results clearly showed that the fabric had self-extinguishing properties, extinguishing the flame immediately when the flame was removed.

Observation of the knitted fabric after combustion revealed that the fibers were not strongly fused to each other even in the combustion part.Also, when the fibers of the present invention were subjected to a dyeing test in the same manner as in Example 1, blue dyeing was observed. The staining rate was 79%, indicating good staining properties.

Comparative example 1 Manufacture of poly(metaphenylene isophthalamide).

2t equipped with stirrer, thermometer and jacketed dropping funnel
250.29 (1,232 mol) of isophthalic acid chloride and 600 mol of anhydrous tetrahydrochloride were introduced into a jacketed separable flask and dissolved therein, and the contents were cooled to 20° C. by passing a refrigerant through the jacket. While vigorously stirring, a solution containing 400 ml of anhydrous tetrahydrofuran (1K) T1:r-2V7di7-:/133.7f (1,239 mol) was added dropwise over about 20 minutes. The obtained white emulsion was quickly poured into water (water-cooled) containing 2.464 mol of anhydrous sodium carbonate under strong stirring. Immediately, the slurry temperature rose to near room temperature. Subsequently, the slurry was adjusted to a concentration of 11 with caustic soda, and the resulting cake was thoroughly washed with a large amount of water and dried overnight under reduced pressure at 150°C. The obtained polymer had a logarithmic viscosity of 1.4.

Preparation of poly(metaphenylene isophthalamide) fiber The poly(metaphenylene isophthalamide) or PMIA polymer powder was mixed with N-methyl-2-bi-
(NMP) and NMPK were dissolved at a concentration of 22% by weight in a solvent containing 2% + 7) Li(j) and defoamed under reduced pressure at 80°C to prepare a spinning dope containing no air bubbles.Then, at 80°C
Caα240 was held at 80°CKm from a nozzle with hole diameter o, o sw number of holes 100 (6 holes are circular) while maintaining
Discharged at 5.2 t/min into an aqueous coagulation bath containing s I
Qm After passing through a roller that rotates for 7 minutes, passing through a hot water bath at 80°C and thoroughly washing with water, then performing moist heat stretching between rollers in 98°C hot water at a ratio of 2.88 times, and after applying an oil agent. The yarn was dried by passing it through a hot air tank at 150° C. to obtain a spun yarn that had been subjected to wet heat stretching. The spun yarn had a homogeneous cocoon cross section and was 358 denier/100 filaments.

Next, this spun yarn was subjected to dry heat stretching of 1.88 times on a plate at 310°C to obtain poly(metaphenylene isophthalamide) fiber.

The physical properties of the obtained fibers were as follows: single yarn denier: 2, strength: 4.
99/d, elongation = 28.5 inches, Young's modulus = SO'/
d%Tm = 425°C, Tex = 405°C, Tm-
Tex = 20℃, ) (c = 25%, DSR (Tm)
= DSR (425°C 5 = 16 cm) Although this PMIA fiber, which is outside the scope of the present invention, exhibits good general fiber physical properties, its shape stability at high temperatures above the melting point is not as good as that of Example 1, which is within the scope of the present invention. .It was clearly inferior to Example 2.

Next, we created a cylindrical knitted fabric using the above PMIA fibers and conducted a combustion test using it. Although it clearly showed self-extinguishing properties, extinguishing fire immediately when the flame was removed, we observed the knitted fabric after combustion. Then, in the combustion part, the fibers were firmly fused together and the fiber form had completely disappeared.

Comparative Example 2 0-yne7talic acid 166.1f (1,000 mol), isophthalic acid monosodium salt 0.9405F, anhydrous N,N'-dimethylethylurea 1000a/ was charged into a separable flask, the contents were heated to 200°C on an oil bath, and while maintaining this temperature, tolylene-2,4-diincyanate 17
4. Add a solution containing 1F (1,000 mol) dissolved in 200 dK of anhydrous N,N'-dimethyl ether chloride to the dropping funnel.
The mixture was added dropwise over 4 hours, and after continuing the reaction for an additional hour, heating was stopped and the mixture was cooled to room temperature. A portion of the polymerization solution was taken and treated in the same manner as in Example 1, and the resulting polymer had a logarithmic viscosity of 2.0. The polymer concentration in this polymerization solution was 20.0% by weight, and the solution viscosity was 230 voids (B viscosity needle, 80°C).

The above polymerization solution is filtered under reduced pressure at 80°C to prepare a spinning dope that does not contain air bubbles. Then, the pore size was reduced to 0.0 while maintaining the temperature at 80°C.
8m, 80℃ from a nozzle with 300H holes (6 holes are circular)
17. into an aqueous coagulation bath containing 241% Caα maintained at
Discharged at 7M, passed through rollers rotating at 10m/min, passed through a hot water bath at 80°C, rinsed thoroughly with water, and then
2. Moist heat stretching between rollers in hot water at 8℃
．． This was carried out at a magnification of 34 times, and after applying an oil agent, it was dried by passing it through a hot air bath at 150°C to obtain a spun yarn that had been drawn with wet heat.

The spinning yarn has a homogeneous cocoon-shaped cross section of 1310 denier/30
There were 0 filaments. Next, this spun yarn was heated to 310°C.
Poly(4-methyl-1,3-phenylene/inphthalamide) fibers were obtained by dry heat stretching 2.18 times on a plate.

The physical properties of the obtained fiber are: single yarn denier = 2, strength = 4
, 3f/d, elongation=35chi, Young's modulus=81y/li,
Tm==390℃, Tex=290℃, Trn-Te
x=100°C, Xe=25%, DSR(Tm)=DSR
(395°C) = 831%. In this case, the general fiber properties are good, but the dry heat shrinkage at high temperatures above the melting point is very large, and 1cDsR
(Tm+55°C) = DSR (445°C), but the shape of the Fi woven fibers changed significantly after treatment, making it impossible to obtain the correct sample. When the test was conducted, self-extinguishing properties were clearly observed, but the shape change due to shrinkage of the silk fabric during combustion was significant, and when the knitted fabric was observed after burning, the fibers were firmly fused together. Ta.

Example 3 Method for producing 4-biphenylene isophthalate (terephthalamide) Polymerization was carried out using the same equipment and method as in Example 1. Inphthalic acid 149. ! l' (0,9000 mol), terephthalic acid 1
6.61 t (o, 1ooo mol), isophthalic acid monopotassium salt 2.010? , 2600 tJji of anhydrous N,N'-dimethylethylene urea was charged, and after heating and melting at 200°C, 264.39 (1,000 mol) of 3,3'-dimethyl-4,4'-biphenyl diisocyanate was added.
Anhydrous N.

A solution containing 250 f of N'-dimethylethylene urea dissolved in ILIK was added dropwise over a period of 2 hours. After continuing the reaction for 30 minutes,
Cooled to room temperature. A portion of the reaction solution was treated in the same manner as in Example 1, and the resulting polymer had an logarithmic viscosity of 1.7.

The polymer concentration of this polymerization solution was approximately 11.5% by weight,
The solution viscosity was 1j410yN (nu viscometer; 50°C).

The above polymerization solution was made into fibers in the same manner as in Example 1. The physical properties of the obtained fibers were as follows: Single yarn denier = 2. .

Strength = 5.9f/dr, elongation = 30.5%, Young's modulus =
B 5 f/d, Tm=360°C, Tex=256°C,
--Tex=1 10°C, XC=2cl, DSR(T
m) = DSR (360°C) 28%, DSR (415°C)
It had two general physical properties, and its morphological stability was impaired even at temperatures above the melting point.

Patent applicant RiRashi Co., Ltd. Same Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. A fiber made of an aromatic polyamide having characteristics satisfying the following formulas (1) to (6), wherein the aromatic polyamide has an aromatic repeating unit represented by the formula [I]. family polyamide fiber. Tm≧350℃・・・・・・・・・(1) Tm-Tex≧30℃・・・・・・・・・(2) Xc≧10%・・・・・・・・・(3) DE≧10%・・・・・・・・・(4) DSR(Tm)≦15%・・・・・・・・・(5) DSR(Tm+55℃)/DSR(Tm)≦3%・・・
......(6) (where Tm: melting point, Tex: exothermic start temperature, Xc: crystallinity, DE: fiber elongation, DSR (Tm): dry heat shrinkage rate at melting point, DSR (Tm + 55) ℃): Melting point + dry heat shrinkage rate at 55℃) ▲Mathematical formulas, chemical formulas, tables, etc. are available▼・・・・・・・・・
[I] (Ar_1 in the formula ▲ has a mathematical formula, chemical formula, table, etc. ▼,
▲There are mathematical formulas, chemical formulas, tables, etc.▼ It is a divalent phenylene residue represented by. Here R_
1 represents hydrogen or a methyl group, and has a repeating unit having at least one CH_3 group at the ortho position of the phenylene carbon atom directly connected to the nitrogen atom of the amide bond. A
r_2 is a divalent phenylene residue represented by ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and the carbonyl carbon atom of the amide bond is at the 1st, 3rd or 1st position of the phenylene group carbon atom
, directly connected to the 4th position, and the 1 and 3 positions: 1 and 4 positions are 10
It has a repeating unit in the range of 0:0 to 80:20. ) 2. 95 mol% or more of the repeating units of the aromatic polyamide are 2-methyl-1,4-phenylene isophthalamide/
and/or 5-methyl-1,4-phenylene isophthalamide. 3. 95 mol% or more of the repeating units of the aromatic polyamide are 3,6-dimethyl-1,4-phenylene-isophthalamide/and/or/2,5-dimethyl-1,
The aromatic polyamide fiber according to claim 2, which is 4-phenylene isophthalamide. 4. At least 95 mol% of the repeating units of the aromatic polyamide are 3,3'-dimethyl-4,4'-biphenylene-
The aromatic polyamide fiber according to claim 2, characterized in that the fiber is isophthalamide.